It includes, among other things, a link to the Khan Academy Engineering Management Reading List.
See especially the first book on the list about a need for "slack" (free time, not the software) called "Slack: Getting Past Burnout, Busywork, and the Myth of Total Efficiency" by Tom DeMarco". The summary: "There is a tradeoff between efficiency (meeting previous well-defined needs with minimal effort) versus effectiveness (meeting newly emerging needs with flexibility and responsiveness through organizational learning). If you optimize only for efficiency in meeting previous needs from past opportunities, you will by necessity eliminate your organizations's capacity to respond effectively to future needs from newly emerging opportunities. This ability to learn and grow as an organization requires "slack" time. Middle management has a vital role to play in organizational adaptability -- but only if they are not over-scheduled."
Tom DeMarco also previously co-wrote "Peopleware: Productive Projects and Team", another excellent book on software management.
Another informative and funny book in that area is by Michael Lopp: "Managing Humans: Biting and Humorous Tales of a Software Engineering Manager"
Bottom line: you have essentially switched to a new field even if computers are still involved so you need time for self-education and practice and failures and recoveries. As in, ultimately, years to get really good at this new profession the same way it took years and thousands of mistakes to get good at software development as a programmer... (Although mistakes with people are often more personally painful than mistakes that just the compiler yells at you about.)
Something else to be aware of (may not apply to you) is that many of the best software developers have some degree of Asperger's -- but people with Asperger's often have issues dealing with human relationships unless they consciously learn various skills for dealing with people that many other non-Aspies just seem to have intuitively. And even when they get good at those skills (sometimes better than non-Aspies because they make understanding all that a focus or obsession), an Aspie using the logical primary CPU part of your brain all day to do what many other people do essentially with an emotion co-processor can leave one feeling drained at the end of the day. So "promotion" from software developer to manager may often be a step backwards in career satisfaction for top developers. Anyway, that is just another complexity on top of all the other issues a new manager of any sort has to deal with. But as you point out, being a manager has its own satisfaction in helping others grow, so if you can get enough positive feedback from seeing your own leverage increase that way, the benefits of transitioning to becoming a manager may eventually outweigh the costs (especially once the people and organizational skills needed to excel become more routinized).